Planographic-printing element and process of making same



May15,192s. 1,669,416

- W. C. HUEBNER PLNOGRAPHIC PRINTING ELEMENT AND PROCESS OF MAKING SAMEF1166r oct. 15, 1922 5 sheets-snee: 1

Afro/marne.

May 15, 192s. 1,669,416

' W. C. HUEBNER PLANOGRAPHIC PRINTING 4ELEMENT AND PROCESS OF MAKINGSAME Filed oct. 1.6. 1922 srsnee's-snee*v 2 20 am 5M, mf.

Arranz/ Fay/4 May 15, 192s. 1,669,416A

W. C. HUEBNER PLANOGRAPHIC PRINTING ELEMENT AND PROCESS 0F MAKING SAME IFiled Oot- 15', 1922 3 Sheets-Sheet 3 Patented Mnyils, 1928.

UNITED STATES 1,669,416 PATENT OFFICE.

WILLIAM-C. HUEBNEB, F BUFFALO, NEW YORK.

PLANOGRAPHIC]?B.I1"E|?I'JIG. ELEMENT AND .PROCESS-'OF MAKING SAME.

Application illred October 13, 1922. 'Serial No. 594,371.

In direct planographic rinting in which rints are made directly rommetal plates, ithographic stones'and analogous, hard or unyieldingprinting surfaces, great dithculty is experienced'in attempting toproduce high class halftone or similar fine tex-y tured Work on accountof the unavoidable unevenness and rigidity of the printing plates orsurfaces, the unevenness of the paper or other print-receiving materialand the inking rollers, and the consequent great pressure needed tosecure fair printed impressions. The result is -a more or less brokenimpression Where the values are lighter than solid color, and theprocess requires hard, smooth-surfaced paper for printing. g

The above-mentioned difiiculties are mainly overcome in offset printingby the yieldpression from a'metal or other non-yielding printing plateor element and, in turn, prints the impression upon the 'print receivingsurface. Very smooth prints can be made upon either smooth or roughsurfaced papers by this method, but the solid colors lack depth orstrength because the impression upon the paper is really a second step,

I offset from the first impression made upon the rubber blanket. Thisshortcoming, in a Way, is true also of the individual dots or valuesthat make up the halftone or color gradation areas, each lacking itsreal depth of color. Offset printing also has the disadvantage that `itinvolves more steps, and therefore is slower in make-ready than directprinting. Furthermore, it is not as accurate in register for color Workon account of variations in the surface speeds of the differentcylinders of thepress.

One object of this invention is to produce a planographic printing plateor element which is adapted for direct printing and Will give theadvantages but overcome the disadvantages above mentioned, of both theing rubber blanket which takes an ink im-` direct and offset methods ofplanographi l editions by the direct method, and.

up the values in lights andshadows, and at4 the same time insure smooth,unbroken prints upon either smooth or rough surfaced paper and otherprint-receivin material; also to provide means where y the -steps andoperations now required in offset printing are reduced in number, thepresses needed to produce a high class product are simplified, andresults are attained in time, cost and qualit of Work that are notpossible by other nown methods of printing. Still another object oftheinvention. is to supply a practical method for producing planographieprinting plates havingthe before mentioned characteristics andadvantages. v

The resilient or yielding printing element is made preferably bymounting suitable elastic or' resilient material, such as a thin sheetor layer of rubber of fine quality, upon a base of metal or othermaterial of a relatively inelastic n'ature adapted to preventstretching, creeping or distortion 0f the resilient sheet When makingprints from the printing element and to insure accurate register andstability of the resilient printing surface thus formed when printingtherefrom. The sheet rubber or its equivalent can be mounted directly ona thin, metal plate'or sheet, or on a cylinder, and secured thereon, asby cementing. Or a sheet of tough, even paper or film of other suitablecharacter can be iirst cemented on lthe metal base and the sheet rubbercemented on the paper or film, which forms a binder between the rubberand metal and insures a firm, reliable connection of therubber to thenonextensible base. Sheet rubber or other suitable material can beapplied in like manner to the yreverse orvunder side of the metal orbase plate for the purpose of producing a cushion under the metal basecarrying. the resilient printing surface, or a thin piece of felt orother suitable material can be used alone or with a rubber or othersheeton the reverse side of the printing element, depending upon the natureof the Work to be printed, as illustrated in the accompanyingi drawingsin which,

Fig. 1 is a face view of a resilient surfaced printing plateillust-rating one embodiment of my invention. f 'l lFig. 2 is a sectionthereof indicating diagrammatically by raised portions thereon theink-receiving portionsof the printing surface. l

Figs. 3 and 4 are views similar to Figs.

'nisA loo 1 and 2 respectively, but showing a negative of the printingimage of the plate shown in Figs. 1 and 2.

Figs. 5-14 inclusive are similar sections of different modifications ofthe invention.

Fig. is a diagrammatic view of a press equipped with a printing elementaccording to my invention.

As shown in Figs. 1-5 inclusive, the printing element consists ofshee-t16 of yielding material, preferably rubber of fine quality, whichforms the printing surface, and is secured by a suitable cement orbinder 17 on a nou-elastic or non-extensible base 18, which preferablyis a thin metal plate. The raised and depressed portions indicating theprinting image in Figs. 2 and 4 arc greatly exaggerated for the purposeof illustration. In the actual element the surfaces of t-he printing andnon-printing portions of the plate are practically in the same plane, asin other planographic plates.

Fig. 6 shows similar rubber sheets 1G and 16a, similarly secured on bothfaces of the metal base plate 18. The rubber sheet 1Ga on the 'reverseside of the metal plate forms a yielding cushion for the latter.

Fig. 7 shows a printing element similar to that shown in Fig. G exceptthat the cushion 19 on the reverse side of the base plate is made offelt or analogous material.

In Fig. 8 the element is substantially the same as shown in Fig. 6,except that a binder ply of paper or other suitable material isinterposed between the rubber cushion 16a and the metal plate 18. Thisforms a very secure bond between the metal and rubber.

Fig. 9 shows the use of a similar bond 2() in a printing elementconstructed as in Fig. 7, with a feltv cushion 19.

Fig. 10 shows the use of such a bond 2O between the metal plate 18 andthe rubber sheet 16 forming the yielding printing surface.

-F ig. 11 illustrates an element like that shown in Fig. 10, butprovidedwith a rubber cushion 16a.

The element shown inFig. 12 is similar to that shown in Fig. 11, exceptthat a felt cushion 19 is used.

Fig. 13 shows an element having a rubber printing surface 16 and rubbercushion 16, but employing a bonding ply 20 between the metal plate andeach rubber sheet.

Fig. 14 shows a similar combination, except that the rubber cushion isreplaced by a felt cushion 19.`

Various different constructions printing element adapting it fordifferent desired results are thus shown in Figs. 5-14, but still otherconstructions of the printing element'having the yielding printingsurface and a base or strengthening part of a character adapted toprevent stretching or distortion of the yielding printing part of thecould be usedl It is also possible to mount the yielding materialforming the printing surface directly upon a press cylinder or upon atubular cylindrical base adapted to be mounted in a press, although thethin, flexible plate formation of the printing element,` as illustratedin the drawings, is considered preferable because of various practicalconsiderations.

Different methods can be employed for preparing the rubber or yieldingsurface of the printing element for printing therefrom, after firstcleaning it in any suitable way, to remove all grease or other foreignmatter therefrom. For instance, it can be Washed with a solution ofmuriatic or hydrochloric acid, or acetic acid and salt in water; or thesurface can be scoured with any suitable scouring medium.

One method of preparing the printing surface after cleansing it, is asfollows First, the surface is sensitized in one of the well known waysused for sensitizing photographic plates or films, then a 'photographicimage or images is or are made upon the sensitized rubber surface byexposing the light sensitive coating to light through a positive ornegative by photographic contact or projection printing. A greasy oretch-resist solution is applied to the surface of the plate or element,either before or after the exposure thereof to light, and the images aredeveloped with a developing solution of a suitable character, dependingupon the nature of the light sensitive coating. This developing solutionpenetrates the greasy or etch-resist solution and dissolves or removesthose portions of the light sensitive coating which were not hardened orfixed by the light action and leaves the underlying portions of theprinting surface bare and clean. Then, an inkrepellent solution, suchfor instance as a nut gall or chromic acid solution, is applied to theprinting surface, after which the surface is Washed with water and wipeddry or nearly dry. This completes the preparation of the surface.

If the elementis not to be used for printing therefrom for some time,the printing surface is preferably coated with gum and the gum coatingrubbed down smootlr and dry. Thereafter, when the plate is to be usedfor printing, the gum coating is removed by Washing With clean Water soas to -leave the printing surface as it Was before the application ofthe gum. Since rubber does not oxidize by exposure to the atmosphere soreadily as metal, the gumming of the Surface, which is for the purposeof preventing oxidation, is not so essential with the described rubberprinting surface as with a metal plate.

Another method of `preparing the resilient printing surface is to makeink. images upon lOl) that drives the cylinder.

the rubber surface previousl cleaned, as explained, by printing direct ythereon from an original plate suitably inked, by laying down alithographie transfer sheet carrying the inked images, orl by othermethods of applying an ink image on a rubber surface. An ink-repellentsolution, such fory example as before mentioned, is then applied to theprinting surface, after which the surface is washed with water and wipeddry or nearly so. Water will then adhere to the uninked portions of thesurface while the inked portions will repel the water, but will takeink. The surface can, therefore', be damped, inked and prints madetherefrom after the manner' of printing from the ordinary planographieprinting plates. V

The printing plate or element with the resilient printing surfaceprepared by either of the methods explained can be mounted upon aflat-bed press, or preferably on a cylinder A of a cylinder press,indicated diagrammatically in Fig. 15, which is suitably constructed sothat the resilient printing surface is disposed ona circular lineeoincident with or slightly above the line known as the pitchcircumference of a gear The print-receiving paper or material B is heldin position against the printing surface during printing to receive theinked impression therefrom, by an impression cylinder C having a similarsurface diameter. The surface of the impression cylinder can be eitherhard or yielding, according to the requirements of the work`to beprinted, or the impression 'cylinder can be supplied with aresilientsurfaced plate with images produced thereon, as before described, andthis second plate can be inked and treated to yield impressions on thereverse side of the print-receiving sheet, thus operating as aperfecting press.

When printing from the resilient printing surface having the printingimages formed thereon, as explained, the printing surface is damped byordinary damping rollers or other means, so as to place a thinlihn ofmoisture over all portions of the surface except where it is repelled bythe greasy ink images which, however, will readily take greasy ink fromordinary inking rollers and yield impressions directly upon paper orother suitable print-receiving material. If the greasy ink used iscolorless, nonprintable, or not visible, then a water ink can be used toprint from the grease repellent parts. The usual damping with waterwould not then be necessar Fig. l5 shows the printlng element providedat its opposite ends with securing and registering bars 25 which areattached to and remain on the element. These bars are adapted to beremovably secured in seats 26 on the press cylinder and to abut againstrigid parts on the seats or cylinder to accurately register the printingelement both endwise and sidewise on the cylinder, as explained morefully in my Patent No. 1,391,117, datedSept. 20, 1921'.

I claim as my invention '1.,A planographie printing element comprising athin sheet of rubber having a printing surface provided with a permanentprinting image the surface of which is substantially coplanar with saidrubber surface, and a substantially non-extensible base to which saidrubber sheet `is attached and which prevents substantial stretching ofsaid rubber when printing from said element, said base having asubstantially uninterrupted surface forming a continuous backing forsaid rubber sheet.

2. A planographic printing element having a resilient rubber printingsurface provided with ink-retaining and ink-repelling portions adaptedwhen said surface is inked to form an ink image and adapted to produceink impressions of said image, and a base to which said printing surfaceis attached and which prevents substantial stretching of said surfacewhen printing therefrom.

3. A planographic printing element having -aprinting surface of rubberprovided with ink-retaining and ink-repelling portions adapted when saidsurface is inked to form an ink image and adapted to produce inkimpressions of said image, and means which prevent substantialstretching of said rubber.

4. A planographic printing element having a printing surface of rubberprovided with a permanent printing image, the surface of which issubstantially coplanar with' said printing surface, and a substantiallynon-extensible base to which said rubber is att-ached and which preventssubstantial stretching of said rubber, said base having a substantiallyuninterrupted surface forming a continuousbacking for said printingsurface.

5. A flexible planographic printing elementcomprising a thin sheet ofrubber having a printing surface provided with a permanent printingimage the surface of which is substantially coplanar with said rubberprinting surface, and a thin flexible but substantially non-extensiblebase to which said rubber sheet is attached and which preventssubstantial stretching of said rubber when 'printing from said element,said base having a substantially uninterrupted surface forming acontinuous backing for said rubber sheet.

6. The process of making a planographic printing surface which isresilient in a direct-ion normal to said surface but' is substantiallynon-extensible in directions V'parallel with said surface,` consistingin securing .a

thin layer of resilient material such as rubber uniformly andcontinuously throughout the area of said resilient material on a{lexible but substantially continuous and non-extensible base, forming apermanent printing image on said resilient printing surfacesubstantially coplanar with said surface, and treating said resilientprinting surface to cause the portions thereof not covered by saidprinting image to be ink-repellent.

7. The process of making a planographie printing surface which isresilient in a direction normal to said surface but is substantiallynon-extensible in directions parallel With said surface, consisting insecuring a thin layer of resilientmaterial such as rubber uniformly andcontinuously throughout the area of said resilient material on aflaxible but substantially continuous and nonextensible base, coatingthe surface of said resilient material with a light-.sensitive sub'-stance, producing by photography a printing image on said coatedresilient surface and then treating said printing surface to cause theportions thereof not covered by said printing image to be ink-repellent.

8. The process of making resilient planographic printing surfaces,consisting in coating the surface of a resilient material such as rubberWith a light sensitive coating, producing a photographic image on saidsensitized surface by exposing the same to light through a photographicprinting element, applying a greasy or etch-resist solution to saidsurface, developing said image With a developing solution, then applyingan ink-repellent solution to said surface, and then Washing saidsurface.

9. A flexible substantially non-extensible planographic. printingelement having Va.

printing surface of resilient material such as rubber provided With aprinting image the surface of which is substantially coplanar withsaidprinting surface and having a flexible substantially non-yieldinguninterrupted smooth backing for said resilient material.

10. A flexible substantially non-extensible printing element comprisinga thin facing Asheet of a resilient material such as rubber, a thinflexible metal sheet forming a substantially uninterrupted smoothbacking for said resilient facing sheet, and a thin fabric sheetinterposed between and intimately attached throughout to said facingsheet and metal sheet.

1l. A planographie printing elementcomprising a base providing asubstantially continuous uniform backing, said base being composed ofsheet material possessing flexibility but substantially not extensiblein directions parallel to the plane of the sheet, a substantiallyco-extensive sheet of inherently resilientv material, such as rubber,superimposed on said base, said resilient sheet having a direct printingsurface provided With an ink-printing image, fixed on and substantiallycoplanar with said surface, said resilient sheet being substantiallyuniformly slightly compressible against said base in directionssubstantially normal to the printing surface to compensate forvariations When under pressure, and means for securely attaching saidbase and resilient sheets uniformly and continuously throughout theareas of their adjacent surfaces whereby to substantially lprevent anydisplacement of the resilient sheet in directions parallel to thesurface thereof.

WILLIAM C. HUEBNER.

